Expansible chamber motor of fluid volume meters



W. L. BROWN Jan. 26, 1954 EXPANSIBLE CHAMBER MOTOR OF FLUID VOLUME METERS 3 Sheets-Sheet 1 Filed Oct.

FIG: 1-

' INVENTOR:

III

W. L. BROWN Jan. 26, 1954 EXPANSIBLE CHAMBER MOTOR OF FLUID VOLUME METERS 3 Sheets-Sheet 2 Filed Oct. 25, 1950 II /I INVENTOR:

Jan. 26, 1954 w, BROWN 2,667,147

EXPANSIBLE CHAMBER MOTOR OF FLUID VOLUME METERS Filed 001:. 25, 1950 3 Sheets-Sheet 3 INVENTOR.

Patented Jan. 26, 1954 EXPANSIBLE CHAMBER MOTOR OF FLUID VOLUME METERS William Laird Brown, Lansdowne, Pa.

Application October 25, 1950, Serial No. 192,073

16 Claims.

This invention relates to expansible chamber motors of fluid volume meters; and in the exemplification hereinafter described is applied to a gas meter of the positive displacement type. In the meter shown, the gas traverses a pair of opposing bellows, which, through offset flag rods, actuate a linkage mechanism whereby a tangent arm is rotated, said tangent arm being secured to a valve crank shaft by which slide valves are reciprocated to control admission of the gas to and from the bellows.

My invention has for one of its aims to increase meter capacity for a given speed and a given size of case, by providing a longer disc stroke and larger valves than in ordinary meters, at the same time providing an advantageous angularity between the tangent links and the tangent arm, for the purpose of reducing friction and irregularity of operation. This desideratum I realize in practice, as hereinafter more fully disclosed, through improved proportioning and arrangement of the arms and links by which motion is transmitted from the bellows to the valves.

Another object of my invention is to provide additional valve port area, and consequently to increase meter capacity, in a given size of case (over and above the increased valve size mentioned above) by setting the crossbars of the valve seats, and the co-acting valve cover edges, at an angle other than a right angle to the axis of valve cover motion.

Another object of my invention is to provide a valve cover which will operate quietly, and with a minimum of friction, under various conditions of dryness and gumminess of valve covers and valve seats; and which will avoid a tendency to uneven wear and tilting of the valve cover during operation.

Other objects of my invention are to provide a fork channel and a diaphragm channel of ample cross section for passage of gas through the meter, with consideration of the larger valves used, forming and disposing these channels so that interference with the diaphragm is avoided, and overall meter height reduced.

Another object of my invention is to reduce or eliminate vertical offsets in the crank arms by disposing the valve seat surfaces at different heights above the valve table.

Another object of my invention is to provide a single inner valve guide to control both front and back inner valve guide wires, said wires being arranged at different heights above the valve table.

Another object of my invention is to arrange the inner and outer valve guide wires, with their controlling valve guides, to give ample space for re-grinding valve seats, and permit the seats to be set more closely to the outlet end, as more fully described hereafter.

Other objects and attendant advantages will appear from the following description of the attached drawings, wherein Fig. 1 is a staggered horizontal section of a gas meter, partly diagrammatic, conveniently embodying the present improvements, viewed from above, with certain parts removed or broken out for the sake of clearness, including the front valve cover, the front outer valve guide wire, and part of the front inner guide wire;

Fig. 2, a staggered longitudinal section of the meter viewed from the front, with certain parts broken out or removed, including both valve covers and their valve guide wires;

Fig. 3, a section of the front outlet corner of the meter, viewed from above, partly diagrammatic, to show an alternative to the valve seats and covers of Fig. 1, namely seats and covers with valve seat crossbars set at an angle to the axis of valve cover motion other than a right angle; the figure being drawn to the same scale as Fig. 1;

Fig. 4, a sectional elevation of the valve cover, as indicated by the arrows IV, IV of Fig. 1;

Fig. 5, a sectional elevation of the valve cover, with a view of the crank arm in section, as indicated by the arrows V, V of Fig. 1, the valve guide wires and their mountings being omitted in Figs. 4 and 5 for a clearer representation of the cover structure;

Fig. 6, a longitudinal section of part of the meter viewed from the front, showing an arrangement of crank arms and valve seats alternative to that shown in Fig. 2;

And Fig. '7, a perspective view of the fork channel.

The gas meter delineated for convenience of exemplifying my invention is generally of well known construction, having a generally rectangular casing I, with a horizontal valve table 2 setting apart a comparatively high lower compartment 3 and a shallower upper compartment :2. The upper compartment 4 is closed at front and back by front gallery 5 and back gallery 6 respectively. The lower compartment 3 is in turn sub-divided by a central longitudinal partition 1 into two chambers for the two bellows of the meter, closed on the side away from the partition by discs 9. The inlet end 59 of the the disc 9, but being of well known construction.

are not further indicated or described. Leading from the gas inlet I l is the long channel, l3, in this instance above the valve table 2, by which channel gas is conducted to a valve box I l con.- taining the valves !5, whereby the admission of gas to, and exhaust from, the bellows'B are controlled. Gas may be conducted from the inlet H to the valves E5 otherwise than herein shown, by

way of example, without affecting the advantages of my invention. Each of the valves l5 comprises a valve cover [6 which moves back and forth over a valve seat I! to connect the outer ports i8 and i9 alternately with the center port 20, port 23 being separated from ports 18- and [9 by crossbars 2i and 22 respectively. The diaphragm port 48 communicates with the inside of the bellows 8 through the diaphragm channel as indicated in Fig. 2 while the case port (9 communicates with the outside of the bellows 8.

The center ports 29 lead into the branches of a fork channel 24, by which gas is conducted to the outlet 25 as shown by dotted lines in Fig. l, the front branch only being shown. The rear branch is omitted from Fig. l to permit a clearer representation of valve l5 atback of meter.

Each bellows 8 has a disc 9, the motion of which, by fiag carriages 26 and 2?, is transmitted to the offset flag rod 28, which combines the functions of flag rod, flag, and rock shaft of other designs of meters. The horizontal distance between the flag rod axis a--a and the axis of the offset portion of the fiag rod, 11 l), may be taken as the effective flag length. Flag rod 23 is journalled in bearing 29 fixed to the bottom 30 of the meter casing I, thence extending upwards to the oifset portion 3|, which is operatively connected to the disc 9 as explained; and then, returning to the axis afl-a, extends through the gas-tight stuffing box 32' into the upper compartment 4. Afiixed to the upper ends of the flag rods 28 are flag arms 32 and 33, which, through tangent links 34 and are connected to thetangent post 36. The vertical axes'of the bearings which connect the fiag arms 32 and 33 with the tangent links 34 and 35 respectively are indicated by points 0 and d in Fig. 1. The tangent post 36 is set on the tangent arm 31, and is adjustable thereon by a well known device not further described.

The bulge 192 in the inlet end 18 provides clearance for the movement of the front flag arm 32. The bulge 33 in the back gallery 6 provides clearance for the movement of the rear flag arm 33.

The tangent arm 3? is fixed to the valve crank shaft 39, which is journalled near its upper end in the kingpost cc. The valve crank shaft 39 carries the worm 4!, which drives the index through the horizontal axle. As index and horizontal axle are of well known type, they are indicated diagrammatically only in Fig. l, by f-f and e-e respectively.

The valve crank shaft 39 passes through the gas tight stufiing box 42 into the channel 13,

there reciprocating the valve covers l6 on the valve seats 11, 96, by means of crank arms 43, 44, connected to valve wrists 45, 46. The valve covers are confined to straight line motion by outer valve guide wires 41 and inner valve guide wires 48, 49, engaging respectively outer valve guides 50 and an inner valve guide 5!.

The refinements which I have made for the attainment of the practical advantages hereinbefore pointed out are as follows:

In (9) and (h) below are given certain changes from ordinary meter design disclosed in U. S. Patent No. 2,313,515, granted to me March 9, 1943, these changes being also combined in the present invention. In (1) below is described an improved arrangement of flag arms and tangent links, difiering from Patent No. 2,313,515, and forming part of the present invention.

(g) Lengthening the stroke of the diaphragm disc increase the volume of gas delivered per revolution of the meter; by which either increased meter capacity for a given size of case, or slower meter speed at a given delivery per hour, or both together, may be secured. However, if' the disc stroke is increased in the ordinary design of meter, which design is shown generally in U. S. Patent No. 9591, granted to Alexander Angus Croll on February 22, 1853, the diameter of the circle described by the tangent post is increased, and the tangent links are shortened, both these changes increasing the angularity between the tangent links and the tangent arm, and consequently increasing friction and irregularity of operation. My invention permits increasing the disc stroke to secure the advantages mentioned, without producing undue angularity between tangent links 34, 35, and tangent arm 3'5, explained thus:

In the first place, the flag rods 28 of my invention are positioned, as on a plane passing through the flag rod axes aa, and the corresponding axis of the rear flag rod, this plane being appreciably further from the bellows axis j-a' than in the ordinary meter. Thus the eifective fiag length is increased and the angle of flag arm sweep is reduced, for a given disc stroke; and decrease in like proportion is made in the diameter of the circle is described by the tangent post 36. The angle of effective flag arm sweep is 50L shown diagrammatically on Fig; 1 as angle m,

and the extreme positions of the offset portion of the flag rod 3| are shown as n, p. Obviously, the greatest advantage in this respect will be obtained by positioning the flag rods 28 as close to the adjacent inlet end ID of the casing as possible, of course allowing proper clearance between the inlet end and the front flag arm 32 at the outer limit of the motion of the latter.

Here it should be noted that this shift of the flag rods 28 moves the valve crank shaft 39 in the same direction, usually to a position closer to the inlet H than to outlet 25, in distinction to the ordinary position of the valve crankshaft, namely, closer to the outlet. However, it is to be understood that within the scope of my invention, the flag rods 28 may be disposed in positions other than herein shown without sacrifice of the advantages gained; and that the position of the valve crank shaft 39 may be shifted, to agree with such other positions of the flag rods, towards either inlet II or outlet 25, as compared to the position shown in Fig. 1.

(h) With valve crank shaft 39 shifted considerably towards inlet 1 l as in Fig. 1, the ordinary arrangement of valves with their axes of motion at right angles would position the fork channel 24 and the diaphragm channel 23 correspondingly closer to inlet l I, necessitating a deeper compartment 3 to avoid interference between said channels and diaphragm l2; and necessitating an increase in the lengths of the channels themselves, with consequent increased resistance to gas flow. According to my invention, these disadvantages are obviated by setting the valve axes at an acute angle, and positioning the valves close to outlet 25, allowing larger valves to be set in a given case, and increasing meter capacity. Valve covers [6 move in relation to the discs 9 as if driven by a single crank on axes at right angles as in ordinary meters, by provision of two cranks 52, 53 on the valve crank shaft, shown in elevation in Fig. 2, and diagrammatically in Fig. 1, with the cranks at an angle g to each other. On Fig. 1, 2 is the circle described by the axes of cranks 52, 53, point aa represents the axis of crank 53, and b b the axis of crank 52, at the moment when crank arms 43 and 44 are in the positions shown in the figure. The upper crank 52 with its associated bearing collar 54 is smaller than the lower crank 53 and its bearing collar 55, so that the lower crank arm 43 can be slipped down past the upper crank in assembly, permitting the use of an integral valve crank shaft instead of the built-up types of other designs.

(2') An important change has been made, in the present invention, in the arrangement of the angles 7", 5, through which the flag arms 32, 33 swing. The midstroke position if of the front flag arm 32 is set out of coincidence with the transverse plane of the flag rods, 28, being turned away from the valve crank shaft; and the midstroke position it of the rear flag arm 33 is out of parallel with the longitudinal medial plane of the meter, and also turned away from the valve crank shaft. In other words, the midstroke positions of both flag arms are outwardly offset angularly with respect to the valve crank shaft. As compared to midstroke positions of the flag arms respectively coincident with the plane of the rods and parallel to the longitudinal medial plane of the meter, as in U. S. Patent No. 2,313,515, this change decreases the length of the flag arms 32, 33 and the related diameter of the tangent circle is, and also increases the lengths of the tangent links 34, 35, by both these changes bettering the angularity between the tangent links 34, 35 and the tangent arm 31.

The importance of this change may be indicated as follows: the thrust or pull on the tangent post 35 as it moves around the tangent circle 7c is the resultant of the thrust or pull of the two tangent links 34, 35. At only four points around the tangent circle, and then only momentarily, is this resultant at right angles to the tangent arm 31, at those instants exerting maximum turning moment. At all other points, the resultant is at other than a right angle to the tangent arm 3?, and at those other points the resultant is equivalent to a smaller turning force at right angles to the tangent arm, and a component exerted axially to the tangent arm. This axial thrust or pull of course provides no turning moment, and is expended in overcoming friction and temporarily displacing parts. measure of the angularity between tangent arm and tangent links, an angularity quotient may be taken, equal to the diameter of the tangent circle lc divided by the length of the tangent link. As this angularity quotient is increased, an in- Asa-'- crease likewise occurs in axial thrust or pull on the tangent arm 31, in total variation, over a revolution, of this axial thrust or pull, and in total variation, over a revolution, of right angle thrust or pull. Increase in these three conditions is unfavorable in respect to the friction and pressure fluctuations of the meter in motion, and therefore reducing the angularity quotient is important to meter operation.

On the effect of friction on the proof of a. meter, it may be noted that wear arising from friction at all bearing points between and including the valve crank shaft 39 and bearing 29 causes lost motion which allows the disc 9 to travel further at each end of its stroke, thereby delivering more gas per revolution and causing a slow meter. Wear at the bearings of the crank arms 43, 44, causes the valve covers "5 to run slow in relation to the movement of disc 9, which also makes the proof of the meter slow. For meter accuracy, therefore, it is important to reduce wear at the bearings, as contemplated in this invention. Increased friction also reduces meter capacity, by absorbing a greater proportion of the allowed pressure drop through the meter.

The change indicated under (2') above, by decreasing the diameter of the tangent circle is and increasing the length of the tangent link 35, considerably decreases the angularity quotient for a relatively small change in the dimensions of the parts. Consequently, a longer disc stroke (ll-77, on Fig. 1) with increased meter capacity at a given speed, may be used, without excessive angularity by the arrangement indicated under (2') or, for a given stroke, the angularity may be considerably bettered, with theoperational advantages mentioned,

In Fig. 3 an alternative design of valve is shown, the crossbars 56, 51, 58, 59 of the valve seat and the co-acting edges 60 of the valve cover 6|, being set at other than right angles to the axis of valve cover motion 2J-U. The valve wrist is shown diagrammatically as 62, the crank arm as 63, the valve crank as 54, and the valve crank shaft as 65. Inner and outer valve guide wires 66, 6! and inner and outer valve guides 68, 69 are shown, similar to those of Fig. 1. The extreme position of one edge of the valve cover 6! is shown at w-w.

The areas of the valve ports 10, H, #2 in Fig. 3 are about 20% greater than the areas of the corresponding ports 18, 26, [9 of Fig. 1, although the limiting clearances in the two figures are about equal. Thus a considerably larger valve port area can be provided under Fig. 3 than under Fig. 1, allowing about the same operating clearances in each case, in a given size of meter.

As a less important advantage of the design of Fig. 3 in respect to meter capacity (besides the increase in port area) it will be seen that the center port H points more directly towards the outlet than does port 20 of Fig. 1.

For maximum utilization of available space, the ends of the flag arms 32, 33 are arranged to swing under the upper flanges of the meter oasing, as at T3 in Fig. 2, ample vertical clearance being provided. To connect with the tangent post 36 without increasing overall meter height, tangent links 34, 35 are offset upwardly, as at 14, Fig. 2.

Under certain conditions of gumminess from condensation on the valve seats, valves of ordinary-design are apt to produce a strange variety of noises very annoying to consumers, and the sourceof. many complaints to the gas company. The; position of the valve wrist. in the ordinary meter applies a. part of the weight of the crank arm at a considerable distance from the center of gravity of the combined valve cover, valve wrist, and valve guide wires, which condition may be added to by the differing lengths and weights of the inner and outer valve guide wires. Further, in some designs of meters, the crank arm is journalledon the valve wrist at a considerable height abovethe valveseat. Either of these conditions, or the two in combination, tends to give a tilting effect to the valve cover, causing uneven wear on the valve seat, leakage of gas, and the noisiness. already mentioned.

The construction shown in Figs. 4 and 5 sets the axis of the valve wrist 01-51: on a vertical line running through the, center of gravity of the moving body composed of the valve cover, the two valve guide wires, and the valve wrist itself, this vertical line being on or in close proximityto the midpoint of the plan contour of the valve cover; and also sets the valve wrist close to the valve seat. The valve wrist 45 is so positionedin adepression is fashioned in the dome 16 of the valve cover, which depression runs completely across the valve cover in the direction of the axis of valve cover motion. As shown, clearance is provided between. the lower surface Tl of the crank arm 44 and the bottom 78 of the depression in the dome 15. Thus that part of the weight of the crank arm 44 carried by the valve cover, through the horizontal bearing surface 19 of the valve wrist 46, is evenly distributed over the surfaces in. contact on the valve cover andvalve seat; and this feature, in conjunction with the application of the thrust or pull of the crank arm 44 at a level near the valve seat, prevents the tilting effect mentioned. and its unfavorable consequences.

To keep the vertical line through the center of gravity on, or in close proximity to, the midpoint of the plan contour of the valve cover, it is necessary, in the embodiment shown in Fig. 1,

to compensate'for the extra length of the inner valve guide wire 49, which may be effected by increasing thediameterof the shorter outer valve guide wire 41, or by adding cover material'in the region of the valve cover diagonally opposite to the inner valve guide wire, as at 80.

In the substitution'of this construction of valve cover for the valve cover arrangement shown in U. S. Patent, No. 2,313,515, in which the valve wrists were placed on the side of the valve cover nearest to the valve crankshaft, a further, advantage is gained by lengthening the crank arms 43, 44 to or near the midpoint of the plan contour of the valve cover. This reduces the angularity of the crank arms 43, 44 for a given crank throw, thereby reducing the side thrust of the valve guide wires 41, 49, on their respective valve guides 59, 5|, and permitting a better synchronization of diaphragm disc travel with valve cutoff and exhaust.

The fork channel 24 providedis shown in Figs. 1, 2, and 7, and will be described as if formed of sheet metal with substantially plane faces, separated by lines substantially straight, for the sake of clearness in representation and description, and further to indicate that the entire fork channel, including both front and rear branches (rear branch not shown) may be formed from a single plane sheet, if desired, with little or no distortion of the metal except bending along straight. lines. It will be obvious, however, that vention, by the use of forming tools, with some or all faces varying from planes, and with some or all of the separations between the faces varying from straight lines, if such changes are deemed of advantage.

Moreover, I do not wish to limit myself to the outlines of the faces of the fork channel, and1to the contour of the separations between the faces, indicated hereinafter as an exemplification of my invention, and shown in Figs. 1, 2, and 7, as it will be evident that both the outlines and positions of the faces, and the contour of their separations, may be changed without departing from the spirit of the invention.

The front branch of the fork channel, referring to Fig. 1, is bounded by the following plane figures:

(A) The triangle 8i82-83 (inner wall) af-.

fixed on its upper edge to the bottom of crossbar 2i, and inclined from the vertical towards the outlet 25 to avoid interference with the diaphragm I2. The edge 83-8| runs from the valve table 2 to the outlet casing end 84. Part of the longitudinal partition I is cut out between 82 and 8| to receive the fork channel on the medial plane of that channel.

(B) The pentagon 85--86-8'!90-89 (outer wall) aflixed on its upper edge to the bottom of crossbar 22, This pentagon may be parallel to plane A, or set at a smaller angle with the valve table 2 for the purpose of providing a greater branch cross sectional area, which branch will then be wider at the bottom than at the top.

(C) The quadrilateral 8l-83-B6-8! (bottom) extending between the bottom edges of planes A and B.

(D, E) Two triangles, 88--89-90 and 83-87- 36, used as closure areas, and not needing further description.

The rear branch of the fork channel, not shown, is identical with the front branch, except for being of the other hand to the front branch.

By this design a fork channel is provided of ample cross sectional area for the gas passing through the center port 28 of the valve seat, and permitting the diaphragm 12 to be set closer to the valve table 2 than in ordinary meters where the walls of the fork channel are vertical. Further, gas passes to the outlet 25 more directly, with lessobstruction and change of direction, than in fork channels of ordinary design. Final-' 1y, a fork channel under the present invention favors the use of diaphragm channels of considerable width, mentioned in the succeeding paragraph.

The diaphragm channel 23, which delivers gas to the inside of bellows 8, is connected with the diaphragm port I8 of the valve seat, and extends from the valvetable 2 at 92 to the outlet end 84 at 93. This considerable width parallel to the longitudinal partition 1 allows provision of adequate cross sectional area for passage of gas with only a comparatively small dimension at right angles to the partition, in the region of the diaphragm channel adjacent to the diaphragm 12, thus affording convenient diaphragm clearance. The diaphragm channel '23 in the region of its lower edge is substantially U shaped in cross section, and passes through a notch in the inner diaphragm ring in the usual manner, thus providing a gas passage to the inside of the bellows. 'Above the region of-its lower.- edge, the diaphragm channel is formed so that its upper edge contacts the fork channel 24-, in the embodiment shown along the edge 8|--83, and contacts the table 2 on the line 8392, and thence runs from 92 to the longitudinal partition 1 in a line approximately at right angles to the-partition. With the diaphragm channel so positioned, it is soldered in place to form a gas-tight duct between the diaphragm port of the valve seat IT and the inside of the bellows.

A bulge 95 is provided in the valve table 2, concave downwardly, for the purpose of'allowing the top of the diaphragm l2 to be set close to the plane of the valve table, or even above it, with proper clearance between diaphragm and valve table still maintained. This results in decreased overall meter height.

The upper surface of the front valve seat i7 is set at a smaller height above the valve table 2 than the upper surface of the rear valve seat 96 (Figs. 1 and 2) thus permitting the use of horizontal crank arms d3, 45 without vertical offsets, for the sake of smooth valve cover motion. In the ordinary meter, driving two crank arms one above the other on the same journal, the lower crank arm is usually tilted upward from the horizontal, and the upper crank arm downward, to register With valve seats of the same height above the valve table, which does not conduce to the best valve cover operation.

Moreover, the provision of valve covers operating at different heights above the valve table is convenient in setting inner valve guide wires 48, 49 at different heights as hereinafter described, although not necessary for that arrangement.

Alternatively, as in Fig. 6, it may be convenient to compensate for the difference in height above the valve table 2 of the different positions on the valve crank shaft of the crank arms thereon journalled, partly by a difference in height above the valve table of the valve seats 91 and 98, and partly by a vertical oiiset in one crank arm 99, shown at Hill.

The outer valve guide wires 4! are fastened to the valve cover [6 between the axis of valve cover motion yy and the valve cover edge H3! adjacent to the front or back gallery 5 or 6 respectively, and substantially distant from said edge, in such a position that maximum travel of the valve guide wire is provided into the corner between the gallery and the outlet casing end 84. Each outer valve guide wire is controlled by an outer valve guide 59.

The inner valve guide wires 48, 49 are fixed to the valve covers between the axis of valve cover motion y--y and the valve cover edges I02 nearest the longitudinal medial plane of the meter. Both these valve guide wires are controlled by a single inner valve guide 5| instead of two as usual, crossing in the valve guide at difierent heights above the meter table 2. This permits the single inner valve guide to be set at an advantageous distance from valve seats 11, 95, for adequate clearance in grinding seats. In the usual arrangement of inner valve guides, two guides controlling the inner valve guide wires separately on the same lines of motion as shown for inner guide wires 48, 19 would have to be set closer to the valve seat than the single inner valve guide 5| of my invention, having due respect to clearance with crank arms 43, 44.

The combined arrangement of valve covers I6, inner and outer valve guides 5 l 59, and inner and outer valve guide wires d1, 48, 69, permits the valve covers to be set close to the outlet end, provides adequate clearance for re-grinding seats,

and substitutes one inner valve guide for the two guides of the ordinary meter. Moreover, the entire space available between the corner of the valve table 2 on one side of the axis of cover motion, and the region of the motion of the crank arms 33, 44 on the other side of said axis, is utilized for the movement of valve covers and valve guide wires, plus necessary clearances. This favors the use of large valves, with consequent increased meter capacity, as aimed at in other parts of my invention.

I do not of course consider myself limited to the precise details of construction shown and described, since under the scope of the broader of the appended claims, these details are subject to considerable variation, as will be readily apprehended by those familiar with this art.

While I have shown and described my invention in connection with a gas meter of a specific type, certain of the features can obviously be used with other kinds of meters within the scope of the appended claims.

Having thus described my invention, I claim:

1. In a fluid volume meter, 9. pair of diaphragms; a casing having an outlet; a valve table, within the casing, having valve seats with diaphragm ports, center ports, and case ports separated by crossbars; valve covers reciprocating on the seats; a fork channel, for conducting fluid from the center port to the outlet, having two inner walls aflixed at their upper edges respectively to the two crossbars between the diaphragm ports and the center ports, and having two outer walls aiflxed at their upper edges respectively to the two crossbars between the center ports and the case ports; both inner and outer walls being inclined from the vertical towards the outlet to provide clearance for the diaphragms, and to provide adequate cross sectional area in the fork channel.

2. The invention according to claim 1, in which the crossbars of the valve seats, and the co-acting edges of the valve covers, are disposed at other than right angles to the axis of valve cover motion.

3. In a fluid volume meter, a casing having an outlet end; a diaphragm and a longitudinal partition within said casing; a valve table within the casing having a valve seat with a diaphragm port; a diaphragm channel for conducting fluid from the diaphragm port to the interior of the diaphragm; a portion of the diaphragm channel adjacent to the longitudinal partition extending from a point on the junction of the longitudinal partition and the valve table to a point on the junction of the longitudinal partition and the outlet end.

4. In a fluid volume meter, a valve crank shaft; slide valves comprising valve seats set on a valve table, and valve covers having valve wrists; the valve crank shaft being connected to crank arms, one above another, by which the valve covers are reciprocated on the valve seats through the valve wrists; the upper surfaces of the valve seats being of different heights above the valve table.

5. In a fluid volume meter, a casing, including front and back galleries and an outlet end; slide valves, comprising valve seats having crossbars set on a valve table, and valve covers; said covers having outer valve guide wires afilxed between the axis of valve cover motion and the edges of the valve covers adjacent to the front and back galleries respectively, but separated from said edges by substantial distances, and positioned so that the outer end of each outer valve guide wire is substantially equi-distant from the outlet end and the adjacent gallery at the extreme outward travel of said outer valve guide wire; said covers having a front inner valve guide wire and a rear inner valve guide wire affixed respectively between the corresponding axis of valve cover motion and the edges of the valve covers adjacent to the longitudinal medial plane of the meter, but separated from said edges by substantial distances.

6. The invention according to claim 5, in which both inner valve guide wires are controlled by a single valve guide, said wires being set at different heights above the valve table to provide clearance.

7. The invention according to claim 5, in which the crossbars of the valve seats, and the co-acting edges of the valve covers, are disposed at other than right angles to the axis of valve cover motion.

8. In a fluid volume meter, a casing, having an end; a pair of bellows within said casing; slide valves, comprising valve seats with cross bars, and valve covers, for controlling flow of fluid into and out of the bellows; motor mechanism deriving movement from the bellows for actuating the valve covers, including a valve crank shaft, crank arms connecting the valve crank shaft with the valve covers, a tangent arm on the valve crank shaft, front and rear flag rods, and front and rear flag arms on the rods connected by tangent links to the tangent arm, the midstroke positions of the flag arms being outwardly offset angularly in relation to the valve crank haft, the front flag arm position being outwardly offset from a plane substantially coincident with the transverse plane of the rods, and the rear flag arm position being outwardly offset from a plane passing through the rear flag rod substantially parallel to the longitudinal medial plane of the meter.

9. The invention according to claim 8, in which the portion of the end above the bellows axis is substantially in a vertical plane, and the front and rear flag rods are in close proximity to said portion of said end.

10. The invention according to claim 8, in which the valve crank shaft is to one side of the bellows axis, and the flag rods are further remote from the bellows axis than the valve crank shaft, and on the same side of said axis as said shaft.

11. The invention according to claim 8, in which the axes of motion of'the valve covers are in acute angular relation.

12. The invention according to claim 8, in

12 whichthe valve crank shaft has plural cranks. 13. The invention according to claim '8, in

which the valve crank shaft has cranks of different diameters to facilitate assembly of the crank arms.

14. The invention according to claim 8, in which the cross bars of the valve seats, and the co-acting edges of the valve covers, are disposed at other than right angles to the respective axes of valve cover motion.

15. In a fluid volume meter, a valve crank shaft; a valve seat; a valve cover having a dome, guide wires, and a valve wrist; a crank arm connecting said shaft and said cover, and imparting a reciprocating motion to said cover on said seat; a depression extending completely through the dome in the direction of the reciprocating motion of the cover, in which depression the valve wrist is set close to the valve seat; the axis of the valve wrist being on or in close proximity to a vertical line through the center of gravity of the body comprising the valve cover, the guide wires, and the valve wrist itself.

16. The invention according to claim 5, in which the axes-of valve cover motion are in acute angular relation, and the cross bars are disposed to the axes at other than a right angle, and at such an angle that the two corners of each valve cover nearest to the casing are substantially equidistant, one corner from the adjacent gallery and the other from the outlet end,-at the extreme outward position of the valve cover.

WILLIAM LAIRD BROWN.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 919,841 Etzel Apr. 27, 1909 1,149,716 Britton "Aug. 10, 1915 1,583,694 Lambert May 4, 1926 1,647,598 Wilson Nov. 1, '1927 1,847,524 Dezendorf Mar. 1, 1932 2,053,734 Ott Sept. 8, 1936 2,223,555 Derbyshire et a1. Dec. 3, 1940 2,281,671 Brown May 5, 1942 2,313,515 Brown 1 Mar. 9, 1944 2,464,499 Gilmore Mar. 15, 1949 2,519,806 Wilson et a1 Aug. 22,1950 2,544,665 Gilmore Mar. 13, 1 951 2,557,460 O-tt June 19, 1951 2,599,514 Menkemeller June 3, 1952 

